Electrosurgical instrument

ABSTRACT

An electrosurgical forceps includes a shaft that extends from a housing of the electrosurgical forceps. An end effector assembly is operably coupled to a distal end of the shaft and includes a pair of first and second jaw members. Each jaw member has a jaw housing and an electrosurgical seal plate. The first jaw member is movable relative to the second jaw member from an open configuration to a clamping configuration. The first jaw member includes an elongated channel defined in its respective jaw housing and extends along a length thereof. A drive assembly operably couples to the first jaw member via a drive rod that is engageable with the elongated channel to move the first jaw member from the open configuration to the clamping configuration and to provide a closure force between the jaw members when the jaw members are in the clamping configuration.

CROSS-REFERENCE TO RELATED APPLICATIONS

This application is a continuation application of U.S. patent application Ser. No. 13/247,795 filed on Sep. 28, 2011, the entire contents of which are incorporated by reference herein.

BACKGROUND

1. Technical Field

The present disclosure relates to an electrosurgical instrument and, more particularly, to an electrosurgical instrument including a drive assembly in operable communication with an end effector to effect movement of one or both of a pair of jaw members from a spaced-apart configuration to a closed or clamping position.

2. Description of Related Art

Electrosurgical forceps are well known in the medical arts. For example, an electrosurgical endoscopic forceps is utilized in surgical procedures, e.g., laparoscopic surgical procedures, where access to tissue is accomplished through a cannula or other suitable device positioned in an opening on a patient. The endoscopic forceps, typically, includes a housing, a handle assembly including a movable handle, a drive assembly, a shaft and an end effector assembly attached to a distal end of the shaft. The end effector includes jaw members that operably communicate with the drive assembly to manipulate tissue, e.g., grasp and seal tissue. Typically, the endoscopic forceps utilizes both mechanical clamping action and electrical energy to effect hemostasis by heating the tissue and blood vessels to coagulate, cauterize, seal, cut, desiccate, and/or fulgurate tissue.

To effect movement of the jaw members, certain types of endoscopic forceps utilize a cam slot and cam pin configuration located at a distal end of the shaft adjacent the jaw members. In particular, a drive rod of the drive assembly, typically, includes a cam pin extending from a distal end thereof. The cam pin is, typically, integrally formed with the drive rod or, in certain instances, is operably coupled thereto via one or more coupling methods, e.g., soldering, brazing, welding, etc. The cam pin is operably coupled to one or more cam slots that are disposed on the jaw members. For example, in the instance where each of the jaw members is configured to rotate or move, i.e., a bilateral jaw configuration, each of the jaw members may include a respective cam slot that is configured to operably couple to the cam pin on the drive rod. Alternatively, one of the jaw members is movable with respect to the other jaw member, e.g., a unilateral jaw configuration. In this instance, one of the jaw members includes a cam slot that is configured to couple to the cam pin on the drive rod.

As can be appreciated, forming a drive rod with a cam pin and, subsequently, positioning the cam pin within the one or more cam slots on the jaw members may increase manufacturing costs of the electrosurgical endoscopic instrument and/or increase production. Moreover, and in the instance where the cam pin is not integrally formed with the drive rod, e.g., soldering is used to join the cam pin to the drive rod, there exists the likelihood of the cam pin uncoupling from the drive rod during use thereof, which, in turn, may result in the electrosurgical endoscopic device not functioning as intended. That is, one or both of the movable jaw members may not move from an open configuration to a clamping configuration or vice versa.

In addition to the foregoing, it is sometimes desirable to provide a specific closure force at the jaw members when the jaw members are in the clamping configuration. To achieve this desired closure force, one or more devices, e.g., a resilient member such as, for example, a spring, may be operably coupled to the jaw members, drive rod, handle assembly, or other device associated with the electrosurgical endoscopic instrument. As can be appreciated, having to add the resilient member to the electrosurgical endoscopic instrument may further increase manufacturing costs of the electrosurgical endoscopic instrument and/or increase production time of the electrosurgical endoscopic instrument.

SUMMARY

An aspect of the present disclosure provides an electrosurgical forceps. The electrosurgical forceps is provided with a shaft that extends from a housing of the electrosurgical forceps. A longitudinal axis is defined through the shaft. An end effector assembly operably coupled to a distal end of the shaft includes a pair of first and second jaw members. Each of the first and second jaw member having a jaw housing and an electrosurgical seal plate. One or both of the first and second jaw members is movable from an open configuration, to a clamping configuration. The moveable jaw member includes an elongated channel defined in its respective jaw housing and extends along a length thereof. A drive assembly operably couples to the moveable jaw member via a drive rod that is engageable with the elongated channel to move the movable jaw member from the open configuration to the clamping configuration and to provide a closure force between the first and second jaw members when the jaw members are in the clamping configuration.

According to an aspect of the present disclosure, the drive rod and the elongated channel are in horizontal registration with one another to facilitate moving the at least one movable jaw member from the open configuration to the clamping configuration. The drive rod may include a generally rounded distal end to reduce a drag force thereagainst during distal translation of the drive rod within the elongated channel. The drive rod may be positioned above a pivot pin that couples the first and second jaw members.

According to a further aspect of the present disclosure, each of the first and second jaw members may be moveable from the open configuration to the clamping configuration. In this instance, the first and second jaw members may include an elongated channel defined in its respective jaw housing and extending along a length thereof. Moreover, the drive rod may include a bifurcated distal end defined by a top portion and a bottom portion that engage the respective elongated channels of the first and second jaw members during distal translation thereof to close the first and second jaw members about tissue. In certain instances, a cutting element may be operably disposed between the top portion and the bottom portion of the bifurcated distal end of the drive rod. In this instance, the cutting element may include a generally arcuate configuration having a cutting edge extending from the top portion of the bifurcated distal end to the bottom portion of the bifurcated distal end to sever tissue subsequent to the first and second jaw members clamping tissue. In certain instances, the elongated channels of the first and second jaw members may include an open distal end that allows the top and bottom portions of the bifurcated distal end to extend therepast during a cutting motion.

Another aspect of the present disclosure provides an electrosurgical forceps. The electrosurgical forceps is provided with a shaft that extends from a housing of the electrosurgical forceps. A longitudinal axis is defined through the shaft. An end effector assembly operably coupled to a distal end of the shaft includes a pair of first and second jaw members. One or both of the first and second jaw members is movable from an open configuration, to a clamping configuration. The moveable jaw member including a camming member having a generally arcuate configuration at a proximal end thereof. A drive assembly is in operative communication with the moveable jaw member via a drive rod engageable with the camming member of the movable jaw member to move the movable jaw member from the open configuration to the clamping configuration and to provide a closure force between the first and second jaw members when the jaw members are in the clamping configuration.

According to an aspect of the present disclosure, the one or more drive rods may include a cutting blade that is operably disposed at a distal end thereof. In this particular instance, the distal end of the drive rod may include a tapered configuration having a shoulder portion configured to contact the generally arcuate proximal end of the at least one moveable jaw member to move the at least one moveable jaw member from the open configuration to the clamping configuration.

A further aspect of the present disclosure provides method for electrosurgically treating and, subsequently, severing tissue. Tissue is positioned between a pair of first and second jaw members of an electrosurgical device that includes a drive assembly with a drive rod having a bifurcated distal end in operative communication with the first and second jaw members. The drive assembly including the bifurcated distal end is configured to move the first and second jaw members from an open configuration for positioning tissue therebetween, to a clamping configuration for grasping tissue therebetween. The bifurcated distal end is defined by a top and bottom portion that have a cutting element operably disposed therebetween. The bifurcated distal end is moved to position the bifurcated distal end between the first and second jaw members to clamp the tissue. Electrosurgical energy is transmitted to seal plates operably disposed on the first and second jaw members to electrosurgically treat the tissue. And, the bifurcated distal end is moved to position the top and bottom portions thereof at least partially past corresponding open distal ends of the first and second jaw members to sever tissue.

According to an aspect of the present disclosure, the type of electrosurgical transmitted may include but is not limited to electrical energy, thermal energy, ultrasonic energy and mechanical energy.

BRIEF DESCRIPTION OF THE DRAWING

Various embodiments of the present disclosure are described hereinbelow with references to the drawings, wherein:

FIG. 1 is a perspective view of an endoscopic electrosurgical forceps according to an embodiment of the present disclosure;

FIGS. 2A and 2B are schematic, side views of a pair of jaw members operably associated with the forceps of FIG. 1 with the jaw members in an open and clamping configuration, respectively;

FIGS. 3A-3C are schematic, plan views of a pair of jaw members according to another embodiment of the present disclosure;

FIG. 4 is a front view of a drive member depicted in FIG. 3; and

FIG. 5 is schematic, plan view of a pair of jaw members according to another embodiment of the present disclosure.

DETAILED DESCRIPTION

Detailed embodiments of the present disclosure are disclosed herein; however, the disclosed embodiments are merely examples of the disclosure, which may be embodied in various forms. Therefore, specific structural and functional details disclosed herein are not to be interpreted as limiting, but merely as a basis for the claims and as a representative basis for teaching one skilled in the art to variously employ the present disclosure in virtually any appropriately detailed structure.

Embodiments of the present disclosure are described in detail with reference to the drawing figures wherein like reference numerals identify similar or identical elements. As used herein, the term “distal” refers to the portion that is being described which is further from a user, while the term “proximal” refers to the portion that is being described which is closer to a user.

Turning now to FIG. 1, an electrosurgical endoscopic forceps 10 (forceps 10) is provided having a longitudinal axis “A-A” defined therethrough, a housing 20, a handle assembly 30, a rotating assembly 70, a trigger assembly 80 and an end effector assembly 100. Forceps 10 further includes a shaft 12 having a distal end 14 configured to mechanically engage end effector assembly 100 and a proximal end 16 that mechanically engages housing 20. Forceps 10 also includes electrosurgical cable 610 that connects forceps 10 to a generator (not shown) or other suitable power source, although forceps 10 may alternatively be configured as a battery powered instrument. Cable 610 includes a wire (or wires) (not shown) extending therethrough that has sufficient length to extend through shaft 12 in order to provide electrosurgical energy to at least one of the jaw members 110 and 120 of end effector assembly 100. As defined herein, electrosurgical energy can include, but is not limited to electrical energy, thermal energy, ultrasonic energy, mechanical energy or any suitable combination thereof. As can be appreciated, the specific configuration of the forceps, i.e., the specific type of electrosurgical energy utilized to treat tissue, may depend on, for example, the type of surgical procedure being performed, the type of tissue that is to be treated, etc. For illustrative purposes, the forceps 10 utilizes electrical energy to electrosurgically treat tissue.

Rotating assembly 70 is rotatable in either direction about longitudinal axis “A-A” to rotate end effector 100 about longitudinal axis “A-A.” Housing 20 houses the internal working components of forceps 10, such as a drive assembly 90 (shown in phantom in FIG. 1), working components of the handle assembly, electrical raceways associated with the cable 610, and other working components therein.

With continued reference to FIG. 1, handle assembly 30 includes fixed handle 50 and a moveable handle 40. Fixed handle 50 is integrally associated with housing 20 and handle 40 is moveable relative to fixed handle 50. Moveable handle 40 of handle assembly 30 is ultimately connected to the drive assembly 90 such that, together, handle 40 and drive assembly 90 mechanically cooperate to impart movement of jaw members 110 and 120 between a spaced-apart position and a clamping position to grasp tissue disposed between sealing surfaces 112 and 122 of jaw members 110, 120, respectively. As shown in FIG. 1, moveable handle 40 is initially spaced-apart from fixed handle 50 and, correspondingly, jaw members 110, 120 are in the spaced-apart position. Moveable handle 40 is depressible from this initial position to a depressed position corresponding to the approximated position of jaw members 110, 120.

End effector assembly 100 is designed as a unilateral assembly, i.e., where jaw member 120 is fixed relative to shaft 12 and jaw member 110 is moveable about pivot 103 relative to shaft 12 and fixed jaw member 120. However, end effector assembly 100 may alternatively be configured as a bilateral assembly, i.e., where both jaw member 110 and jaw member 120 are moveable about a pivot 103 relative to one another and to shaft 12, see FIG. 3A for example. In some embodiments, a knife assembly (see FIGS. 3A-5, for example) is disposed within shaft 12 and a knife channel (not shown) is defined within one or both jaw members 110, 120 to permit reciprocation of a knife blade (see FIGS. 3A-5, for example) therethrough, e.g., via activation of trigger 82 of trigger assembly 80. A more detailed description of a suitable knife assembly including knife blade is discussed below with reference to FIGS. 3-5.

Drive assembly 90 includes a drive a drive rod 91 (FIGS. 2A and 2B) that extends through the shaft 12 for operative communication with the end effector to effect relative movement of the jaw members 110 and 120. In the embodiment illustrated in FIGS. 1-2B, drive rod 91 is positioned above a pivot pin 103 that couples the jaw members 110 and 120. Drive rod 91 is engageable with an elongated channel 114 defined in jaw member 110 to move jaw member 110 from the open configuration (FIGS. 1 and 2A) to the clamping configuration (FIG. 2B) relative to the jaw member 120. Drive rod 91 is configured to provide a closure force at the jaw members 110 and 120 when the jaw members 110 and 120 are in the clamping configuration, described in greater detail below.

In the embodiment illustrated in FIGS. 1-2B, drive rod 91 includes a generally rounded distal end 91 a to reduce a drag force thereagainst during distal translation of the drive rod 91 within the elongated channel 114 (see FIGS. 2A and 2B).

Drive rod 91 and the elongated channel 114 are in horizontal registration with one another to facilitate movement of jaw member 110 from the open configuration to the clamping configuration (FIGS. 2A and 2B) relative to the jaw member 120.

With reference again to FIG. 1, end effector assembly 100 is shown attached at a distal end 14 of shaft 12 and includes opposing jaw members 110 and 120. Each jaw member 110 and 120 includes an electrically conductive tissue sealing surface 112, 122, respectively. Moveable jaw member (in this embodiment jaw member 110), includes the elongated channel 114. In particular, channel 114 includes an opening 115 at a proximal end 113 of the jaw member 110 and extends along a length thereof (see FIGS. 2A and 2B). The length (or depth) and width of the channel 114 is proportioned to accommodate movement of the drive rod 91 therein to achieve a closure force at the jaw members 110 and 120 when the jaw members 110 and 120 are in the clamping configuration. Moreover, and in certain instances, the length (or depth) and width of the channel 114 is proportioned to accommodate movement of the drive rod 91 therein to achieve a gap distance “g” between the jaw members 110 and 120 when the jaw members 110 and 120 are in the clamping configuration. That is, the channel 114 is configured such that contact between the drive rod 91 and interior walls, i.e., an upper interior wall 117, that define the channel 114 limits movement of jaw member 110 past a predetermined position that provides a gap distance “g” between the jaw members 110 and 120 when the jaw members 110 and 120 are in the clamping position, as best seen in FIG. 2B.

In use, jaw members 110 and 120 are, initially, in an open configuration to position tissue therebetween (FIGS. 1 and 2A). Proximal movement of the movable handle 40 drives the drive rod 91 to engage the channel 114 and move within the confines of the channel 114, which, in turn, moves jaw member 110 from the open configuration (FIGS. 1 and 2A) to the clamping position (FIG. 2B). Having the drive rod 91 engage the channel 114 overcomes the aforementioned drawbacks that are typically associated with conventional forceps. In one embodiment, the unique configuration of the drive rod 91 and channel 114 provides an effective method of moving the jaw member 110 from the open configuration to the clamping configuration and an effective method of obtaining a desired closure force (e.g., between about 3 kg/cm³ to about 16 kg/cm³, or in certain embodiments below 3 kg/cm³ and above 16 kg/cm³) at the jaw members 110 and 120 without the need of a cam pin and spring as is typically required with conventional forceps. Additionally, the unique configuration of the drive rod 91 and channel 114 may provide an effective method for maintaining a specific gap distance “g” between the jaw members 110 and 120 when the jaw members 110 and 120 are in the clamping position.

With reference to FIG. 3A, an end effector 200 including jaw members 210 and 220 according to an alternate embodiment of the present disclosure that may be utilized with the forceps 10 is illustrated. Only those operative features that are unique to the functionality of the forceps 10 that utilize the end effector 200 are described herein.

Unlike the jaw members 110 and 120 that implement a unilateral jaw configuration, each of jaw members 210 and 220 is configured to move from the open configuration to the clamping configuration, i.e., a bilateral jaw configuration. In the embodiment illustrated in FIGS. 3A-4, a pair of elongated channels 230 and 240 are operably disposed on respective jaw members 210 and 220. In one embodiment, such as, for example, the embodiment illustrated in FIGS. 3A-3C, the channels 230 and 240 include an open distal end that facilitates cutting tissue clamped between the jaw members 210 and 220. Channels 230 and 240 are configured to receive a respective top and bottom portion 292 a and 292 b of a bifurcated distal end 292 of a drive rod 291.

Top and bottom portions 292 a and 292 b are spaced-apart from one another and collectively define a generally “I” beam configuration, as best seen in FIG. 4. The top and bottom portions 292 a and 292 b, respectively, are each configured to translate within respective channels 230 and 240 as a result of the drive rod 291 translating distally. The top and bottom portions 292 a and 292 b, respectively, and the channels 230 and 240 are configured to function similar that of the drive rod 91 and channel 114. That is, in the clamping position, the top and bottom portions 292 a and 292 b, respectively, and the channels 230 and 240 are configured to provide the requisite closure force at the jaw members 210 and 220 when the jaw members 210 and 220 are in the clamping configuration. Moreover, the top and bottom portions 292 a and 292 b, respectively, and the channels 230 and 240 may be configured to provide the requisite gap distance “g” between the jaw members 210 and 220 when the jaw members 210 and 220 are in the clamping configuration.

A cutting element 250 is operably disposed between the top portion 292 a and the bottom portion 292 b of the bifurcated distal end 292. In the embodiment illustrated in FIGS. 3A, 3B and 4, the cutting element 250 includes a generally arcuate configuration that has a cutting edge 252. The cutting edge 252 extends from the top portion 292 a of the bifurcated distal end 292 to the bottom portion 292 b of the bifurcated distal end 292. The cutting element 250 is configured to sever tissue subsequent to the jaw members 110 and 120 clamping down on tissue. In particular, the cutting edge 252 of the cutting element 250 is “set-back” so as not to sever tissue until the top and bottom portions 292 a and 92 b, respectively, have traveled a predetermined distance within the corresponding channels 230 and 240. That is, a predetermined distance that corresponds to the jaw members 210 and 220 being in the clamping position with the requisite closure force present at the jaw members 210 and 220 and a requisite gap distance “g” between the jaw members 210 and 220 (FIG. 3B). Once tissue is clamped and/or sealed, the drive rod 291 may be moved further distally through a cutting motion such that the cutting edge 252 severs tissue disposed between jaw members 210 and 220. In this instance, the top and bottom portions 292 a and 292 b extend beyond the distal end of the jaw members 210 and 220 to cut tissue, as best seen in FIG. 3C.

In certain embodiments, it may prove advantageous to provide one or more members, e.g., nub, protrusion, detent, indent, etc., in the channels 230 and 240 to indicate to or otherwise inform an end user, e.g., a surgeon, that the top and bottom portions 292 a and 292 b, respectively, have translated a predetermined distance therein. That is, a predetermined distance that corresponds to the jaw members 210 and 220 being in the clamping position with the requisite closure force present at the jaw members 210 and 220 and a requisite gap distance “g” between the jaw members 210 and 220.

In use, jaw members 210 and 220 are, initially, in an open configuration to position tissue therebetween. Proximal movement of the movable handle 40 drives the drive rod 291, which, in turn, moves the top and bottom portions 292 a and 292 b within the confines of the respective cam slots 230 and 240, which, in turn, moves jaw members 210 and 220 from the open configuration to the clamping position (FIG. 3A). The unique configuration of the bifurcated distal end 291 including the top and bottom portions 292 a and 292 b, respectively, is configured to selectively engage the corresponding cam slots 230 and 240 overcomes the aforementioned drawbacks that are typically associated with conventional forceps. Once tissue is clamped and/or sealed, the drive rod 291 may be moved further distally such that the cutting edge 252 severs tissue disposed between jaw members 210 and 220. In this instance, the top and bottom portions 292 a and 292 b extend beyond the distal end of the jaw members 210 and 220 to cut tissue (FIG. 3C).

With reference to FIG. 5, an end effector 300 including jaw members 310 and 320 according to another embodiment of the present disclosure that may be utilized with the forceps 10 is illustrated. Only those operative features that are unique to the functionality of the forceps 10 that utilize the end effector 300 are described herein.

In the embodiment illustrated in FIG. 5, jaw members 310 and 320 include a jaw configuration similar to that of jaw members 110 and 120, i.e., a unitary jaw configuration, wherein jaw member 310 is movable and jaw member 320 is stationary. To move jaw member 310 from the open configuration to the clamping configuration, jaw member 310 includes a camming member 311 of suitable configuration that is configured to contact a distal portion 391 a of a drive rod 391. In particular, the camming member 311 is operably disposed at a proximal end of the jaw member 310 and includes a generally arcuate configuration that upon contact with the distal portion 391 causes the jaw member 310 to pivot about pivot pin 303 to move jaw member 310 to the clamping configuration. Moreover, and in the clamping configuration, camming member 311 may be configured to provide the requisite closure force at and gap distance “g” between the jaw members 310 and 320 (similar to FIG. 2B).

Distal portion 391 a includes a tapered configuration having a shoulder portion 393 configured to contact the camming member 311 of jaw member 310 to move jaw member 310 from the open configuration to the clamping configuration. Distal portion 391 includes a generally elongated neck portion 394 of suitable configuration that extends a predetermined distance from the shoulder portion 393. In the embodiment illustrated in FIG. 5, the neck portion 394 is configured to operably couple to or otherwise support a cutting blade thereon.

Cutting blade 350 is of suitable configuration to sever or otherwise separate tissue. Cutting blade 350 includes a cutting edge 351 having a generally slanted or oblique configuration to facilitate severing tissue. In the embodiment illustrated in FIG. 5, the cutting edge 351 includes a generally flat configuration, although, in certain instances, the cutting edge 351 may be serrated. The elongated portion 391 and cutting blade 350 including cutting edge 351 are configured such that jaw members 310 and 320 will be in the clamping configuration with the requisite closure force at and gap distance “g” between the jaw members 310 and 320 prior to the cutting blade 350 advancing to severe tissue.

In use, jaw members 310 and 320 are, initially, in an open configuration to position tissue therebetween (FIG. 5). Proximal movement of the movable handle 40 drives the drive rod 391. As drive rod 391 is moved distally, the shoulder 393 contacts the camming member 311 of the jaw member 310, which, in turn, moves jaw member 310 from the open configuration to the clamping configuration. The unique configuration of the drive rod 391 and the camming member 311 of the jaw member 310 provides an effective method of moving the jaw member 310 from the open configuration to the clamping configuration and an effective method of obtaining a desired closure force (e.g., between about 3 kg/cm³ to about 16 kg/cm³, or in certain embodiments below 3 kg/cm³ and above 16 kg/cm³) at the jaw members 310 and 320 without the need of a cam pin and spring as is typically required with conventional forceps. Additionally, the unique configuration of the drive rod 391 and the camming member 311 of the jaw member 310 provides an effective method for maintaining a specific gap distance “g” between the jaw members 310 and 320 when the jaw members 310 and 320 are in the clamping position. Once tissue is clamped and sealed, the drive rod 391 may be moved further distally such that the cutting edge 351 severs tissue disposed between jaw members 310 and 320.

From the foregoing and with reference to the various figure drawings, those skilled in the art will appreciate that certain modifications can also be made to the present disclosure without departing from the scope of the same. For example, in certain instances, one or more springs (not shown) may be operably associated with either of the aforementioned end effectors 100, 200 and 300. The one or more springs may be configured to provide a specific closure force at the jaw members, 110, 210, 310 and 120, 220, 320.

While several embodiments of the disclosure have been shown in the drawings, it is not intended that the disclosure be limited thereto, as it is intended that the disclosure be as broad in scope as the art will allow and that the specification be read likewise. Therefore, the above description should not be construed as limiting, but merely as exemplifications of particular embodiments. Those skilled in the art will envision other modifications within the scope and spirit of the claims appended hereto. 

What is claimed is:
 1. An electrosurgical forceps, comprising: a housing; a shaft extending distally from the housing; a drive rod disposed within the shaft and longitudinally translatable therein; and an end effector assembly operably coupled to a distal end of the shaft and including: a first jaw member fixed relative to the shaft; and a second jaw member movable relative to the fist jaw member between an open configuration for positioning tissue between the first and second jaw members and a clamping configuration for grasping tissue between the first and second jaw members, the second jaw member biased toward the open configuration, the second jaw member including an interior wall that defines an elongated channel extending along a length of the second jaw member, the elongated channel configured to receive the drive rod upon distal translation of the drive rod, wherein distal translation of the drive rod within the elongated channel of the second jaw member cams the second jaw member from the open configuration to the clamping configuration.
 2. The electrosurgical forceps according to claim 1, wherein the second jaw member is pivotable relative to the first jaw member about a pivot axis, the elongated channel disposed distally of the pivot axis.
 3. The electrosurgical forceps according to claim 2, wherein the drive rod has a distal end having a rounded configuration to reduce a drag force thereagainst during distal translation of the drive rod within the elongated channel.
 4. The electrosurgical forceps according to claim 1, wherein the drive rod and the elongated channel of the second jaw member are coaxial when the end effector assembly is in the clamping configuration.
 5. The electrosurgical forceps according to claim 1, wherein in the clamping configuration, the drive rod abuts the interior wall of the second jaw member to resist camming of the second jaw member from the clamping configuration to the open configuration to maintain a gap distance between the first and second jaw members.
 6. The electrosurgical forceps according to claim 1, wherein the drive rod is in horizontal registration with the elongated channel to facilitate movement of the second jaw member from the open configuration to the clamping configuration.
 7. The electrosurgical forceps according to claim 1, wherein upon camming of the second jaw member from the open configuration to the clamping configuration, the drive rod abuts the interior wall of the second jaw member to achieve a closure force between the first and second jaw members of between 3 kg/cm³ and 16 kg/cm³.
 8. The electrosurgical forceps according to claim 1, wherein a longitudinal axis defined by the first jaw member is parallel with a longitudinal axis defined by the shaft when the end effector assembly is in both the open and clamping configurations. 